S M L / N J
1 1 0 . 4 0 N E W S
May 21, 2002
WARNING
This version is intended for compiler hackers. The
version ought to be stable, however we have not run
our full regression testing.
http://cm.bell-labs.com/cm/cs/what/smlnj/index.html
Summary:
Significant work in the MLRISC backend. Many improvements
and bugfixes in various parts of the implementation.
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Details:
Libraries:
* added $/controls-lib.cm, a library of configurable "controls"
(In essence, controls are managed ref cells that can be
grouped in sets and put in "registries" to facilitate
configuration and customization via, e.g., environment variables
and command-line arguments.)
$/controls-lib.cm is a distillation of what used to be a CM-only
mechanism. It is now used throughout the compiler.
* bug fixed in IntInf (parsing of hex literals)
* == and != added to INT_INF interface (just placeholders for now)
* added mergeWith function to ORD_MAP interface
* added an implementation of Danvy-style format combinators to
$/smlnj-lib.cm
* priority queues added to Util library (using Okasaki's leftist-tree
implementation)
* updates to $/hash-cons-lib.cm (consR1 ... consR5 added)
* fixed bug in outputSubstr (in TextIO)
* new scrollbar implementation (eXene) courtesy of Allen Stoughton
Basis:
* implemented Knuth-Morris-Pratt string matching and used it
for String.isSubstring, Substring.isSubstring, and Substring.position.
* added {String,Substring}.{concatWith,isSuffix,isSubstring} and
Substring.full
MLRISC:
* jump chaining
* static block frequency calculation
* Ball-Larus branch prediction heuristics implemented
* graphical viewer for control flow graphs added
* treatment of pseudo-ops changed (get emitted first now)
* REMT removed from mltree; DIV and MOD now take a rounding
mode (DIV_TO_ZERO and DIV_TO_NEGINF)
* made generic implementations of DIV_TO_NEGINF more efficient
* CFG edge splitting added
* buggy parts of x86-fp recoded
* added instructions for 64-bit support on x86 (not enabled yet)
CM:
* a new PID generation scheme is in place; it guarantees freedom
from accidental clashes that could subvert the type system but
is "stable" enough to maintain cutoff recompilation properties
* documentation updates
* minor bug fixes
* lambda-split aggressiveness can now be specified on a per-file
basis in init.cmi as well
* CM is now aware of (_)overload, so it calculates dependecies for
it correctly
* support for non-0 entrypoint offsets added
* command-line argument handling for showing/setting controls added
* bug in command-line handling of noweb (in noweb tool) fixed
* improved handling of pathnames in make tool
Runtime:
* fix for bug 1131 (excessive heap usage)
* heap export now silent unless GC messages are on
* fixed assembly code so that X86.prim.asm now compiles without
warnings
* support for non-0 entrypoint offsets added
Compiler:
* cross-module inlining works much better now
* stopgap fix for problem with ppDec in the presence of multiple
declarations of the same type name within one compilation unit
* full support for div/mod/rem/quot added to x86 code generator
* primops added for divisions of all flavors; track those operations
to the backend instead of clumsily macro-expanding them out
at "translate" time
* INLMIN, INLMAX, INLABS parameterized by numkind; use this
to implement all flavors of min, max, and abs
(Real.abs still maps to a separate FP primop.)
* preliminary support for "raw record" allocation and reentrant
C function calls added
* conditional move added to cps (still buggy, therefore disabled)
* _overload now accepted as synonym for overload (when overloading
is enabled); this is for backward-compatibility
* support for non-0 entrypoint offsets added; this (or something
similar) is needed to be able to deal with block reordering
* new, better scaling CPS spill phase
* compiler "knows" its native C calling convention (no longer needs
to be told by ml-nlffigen); X86Backend now split into X86CCallBackend
and X86StdCallBackend
FFI:
* all C FFI libraries now anchored under $c
* tweaks to type encoding (use polymorphism to emulate subtyping)
* encoding of incomplete type is now equal to that of the
corresponding complete type; no more POINTER_TO_INCOMPLETE_TYPE
etc.
(This restores the full generality of the translation -- something
that was lost when we removed functors.)
* support for (optional) mapping enum types to datatypes added
* types in structures C and C_Debug are now equal
* added "witness value" mechanism to ml-nlffi-lib.cm to
implement efficient arbitrary-depth "casts" that strip away
or add "const" modifiers
* ML representation of "" changed so that conversion to C string
is very efficient
Installer/scripts:
* suggestions for more preloads added to config/preloads
* don't use ?_DEFAULT environment variables. (They no longer
exist since we switched to $/controls-lib.cm.)
* buggy transitive-closure algorithm fixed; it caused more things
than necessary to be compiled
Miscellanea:
* minor bug fixes and improvements to mlrisc tools
* mdl tool compiles again, but without anything that depends on
RTL specs (since this is currently broken)
* added #[...] expressions to mlrisc tools